The purpose of this study include (1) To investigate the efficacy of ventilator hyperinflation technique to re-expand lung atelectasis on patients with critical trauma who intubated and mechanical ventilation in the intensive care unit, (2) To investigate the effectiveness of ventilator hyperinflation technique to improve airway clearance on patients with critical trauma in the intensive care unit, and (3) To explore the acute responses of ventilatory functions to ventilator hyperinflation technique on patients with critical trauma who intubated and mechanical ventilation in the intensive care unit.